1. Field of the Invention
Embodiments of the present invention relate to rotational angle detection devices that may be assembled with a throttle valve device for detecting an open angle of a throttle valve.
2. Description of the Related Art
A throttle valve device for controlling flow of air supplied to an automobile engine has been known. The throttle valve device may include a butterfly-type throttle valve that is controlled with respect to its rotation. The butterfly-type throttle valve has a rotational shaft that is rotated according to the operation of an accelerator of the automobile, so that an open angle of the throttle valve is changed to control the flow rate of air supplied to the engine. For this reason, a rotational angle detection device has been assembled with the throttle valve device for detecting the open angle of the throttle valve. The rotational angle detection device may detect the open angle of the throttle valve through detection of a magnetic field that may change according to rotation of the rotational shaft. With the rotational angle detection device, the throttle valve device can control the flow rate of air supplied to the engine while the rotational angle detection device detects the open angle. This type of rotational angle detection device is disclosed, for example, in JP-A-2001-289610.
The information regarding the rotational angle of the rotational shaft of the throttle valve detected by the rotational angle detection device may be transmitted to an external computer. Therefore, the rotational angle detection device may include a sensor terminal member (i.e., a sensor wiring member) for transmitting the rotational angle information to the computer. For example, the sensor terminal member may include four terminals including those for supplying an electric power to the rotational angle detection device, which is necessary for detecting the rotational angle information, and those for transmitting the detected rotational angle information to the computer.
In order to downsize the throttle valve device, some of components of the throttle valve device have been assembled with the rotational angle detection device. For example, a motor terminal member (i.e., a motor wiring member) may be assembled with the rotational angle device in addition to the sensor terminal member. The motor terminal member may include two terminals for connection with a positive side and a negative side of a power source in order to supply an electric power to a drive motor that rotatably drives the throttle valve.
There has been a need in the art for a rotational angle detection device that can be manufactured at a lower cost.